Ozmoo is a brand new Z-code interpreter for the Commodore 64, written by Johan Berntsson and me. As of today, we consider it ready for real-world use.

Z-code is the text adventure format invented and used by Infocom, for games such as Zork, Hitchhiker’s Guide to the Galaxy, Planetfall and more. Z-code allows an author to write a game 100-200 KB in size, and have it playable on a machine with 32-64 KB of memory and a disk drive.

Ozmoo can be used to play all the Infocom games which were released for the C64, but it can also be used to play hundreds of different Inform 6 games which have been developed since then.

Another thing you can do, and this is actually the reason why we started developing Ozmoo, is write your own game in Inform 6 or ZIL and bundle it with Ozmoo to create a standalone game. Ozmoo has the license GPL 2.0. This means anyone can use it for free, redistribute it, use it in games which they give away or sell etc. Ozmoo was written from scratch in 2018 and does not contain any of the interpreter code which was distributed with Infocom games and owned by Infocom.

Ozmoo comes with a Ruby make script which bundles the interpreter with a game file and places the resulting game on one or more D64 disk images. The game can then be played on a real C64 with a 1541 disk drive or a replacement for the 1541, like an SD2IEC, 1541 Ultimate, Pi 1541 etc, or using a C64 emulator. Smaller games can be loaded from tape and played without a disk drive.

Some things Ozmoo supports:

* Z-code version 3, 4, 5 and 8.
* Timed input, as used in Borderzone.
* Named saves (Use a blank, formatted disk for saves, in the same drive as the game, or in a different drive)
* Customizable colours.
* Embedding a custom font (character set). One font is included with the distribution, but you can also supply your own font or, of course, use the system font.
* A small game (story file < about 50 KB) can be stored as a single file which does not require a disk drive to play. Save/restore does require a disk drive.
* A game up to about 190 KB can be stored on one or two 1541 disk sides, and played on a system with a single 1541 drive.
What Ozmoo doesn't support:
* Graphics.
* Sound (except beeps).
* Mouse, paddle or joystick input.
Please note: The Commodore 64 has a 1 MHz 8-bit processor and 64 KB of RAM. Games using a lot of CPU and/or running massive amounts of code on each turn will not be fast enough to be any fun. Infocom games are fast. Inform 5 and 6 games are usually fast enough. ZIL games should be fine. Inform 7 games aren't really playable.
If you are interested in writing a Z-code text adventure, you can check out Inform 6 ( https://www.inform-fiction.org/ ) or ZIL ( https://www.facebook.com/groups/ZILcom/ ). There’s also a friendly forum where you can find more help on getting started: https://www.intfiction.org/forum/index.php